Ceramic kilns

ABSTRACT

A TUNNEL CERAMICS KILN HAS OPENINGS SO ARRANGED THAT WHEN GAPS BETWEEN CARS CARRYING CERAMIC WARE TO BE FIRED ARE ALIGNED WITH THE OPENINGS, APRONS ARE MOVED INTO THE GAPS TO ASSIST IN DEFLECTING HOT GASES INTO THE OPENINGS. THE APRONS MAY BE OF DIFFERING LENGTHS AND IN ONE EMBODIMENT A SINGLE APRON IS USED WITH APERTURES THEREIN.

Feb-9, 1971 mms-KARL. WEINLEIN 3,551,080

CERAMIC KILNS Filed July 25, 1968 v 3 Sheets-Sheet 5 3 r/ )f //l 4 /fr V X/ T l?! 17 3 17 F.l F26. 6.

INVENTOR HANS'KARL WEINLEIN RNEYS United States Patent Office 3,561,080 CERAMIC KILNSv Hans-Karl Weinlein, Ibbenburen, Germany, assignor to Keller Ofenbau G.m.b.H., Laggenbeck, Westphalia, Germany, a joint-stock company of Germany Filed July 25, 1968, Ser. No. 747,580 Claims priority, application Germany, Apr. 18, 1968, P 17 58 180.5 Int. Cl. F27b 9/10 U.S. Cl. 25-142 2 Claims ABSTRACT OF THE DISCLOSURE A tunnel ceramics kiln has openings so arranged that when gaps between cars carrying ceramic ware to be. fired are aligned with the openings, aprons are moved into the gaps to assist in deflecting hot gases into the openings. The aprons may be of differing lengths and in one embodiment a single apron is used with apertures therein.

BACKGROUND OF THE INVENTION The invention relates to a kiln for the ceramics industry, and more particularly a tunnel kiln for heavy ceramic ware, in the -ring zone of which cars loaded with the ceramic ware to be red are placed and in which the kiln gases and the like are evacuated through at least one fire gap situated between two adjacent groups of ceramic ware.

A tunnel kiln arrangement for introducing kiln gases to the kiln tunnel and extracting them therefrom has already been proposed. This consists in its essentials of the door fitted at the charging end of the tunnel kiln, which door, in this known design, is of hollow box construction and contains openings for the passage of kiln gases in the portion facing both the kiln bottom and the firing zone. This hollow lkiln door is connected by pipes to an extraction fan, which draws off the gases flowing into the door.

Because of the construction of this prior proposal, the extraction fan has to be switched off initially during the forward feed sequence. Another drawback of the prior proposal is that the kiln door is necessarily of rather heavy, complicated construction and, even so, affords no guarantee that the flue gases will be properly extracted across the entire kiln cross-section, since the temperature is raised in the gaps at the sides or crown of the kiln, so that temperature differences arise within the grouped ware.

The object of the invention is to provide a kiln in which axial extraction of flue gases over the entire kiln cross-section is possible, without lateral diversion of flow and without the temperature becoming excessive in the gaps at the sides or overhead, and in which there is no risk of creating a wedge of ceramic ware through which the hot gas flow is poor.

SUMMARY OF THE INVENTION By the provision of aprons that can be introduced into the fire gaps the ue gases can be deflected from the tiring zone. The primary advantage of this is that the flow through the ceramic ware being red is entirely axial, so that acceleration of the flue gases and hence a rise of temperature in the gaps at the sides and overhead are avoided, with the result that the temperature within the batches of ceramic ware becomes more uniform.

As the aprons are fitted in the firing zone in such a way that they can be moved, they can be adjusted during the forward feed sequence, so that they do not obstruct the advance of the cars in the kiln.

In one practical embodiment in accordance with the n- 3,561,080 Patented Feb. 9, 1971 vention, with a single apron that can be introduced into a lire gap, this apron is provided with apertures to permit the passage of flue gases and the like. Since the free crosssection is blocked by the apron, apertures being left only for the passage of the Hue gases, these are compelled, while still warm or hot, to ow through the batches of ceramic ware on the cars newly run in and to pre-heat it.

In a modification, the apron is made in two parts, both of which lie in one and the same plane. This kind of apron is of special advantage in a kiln of particularly wide crosssection, because, here again, the flue gases are drawn axially through the ceramic ware.

Where there are several aprons that can be introduced into the lire gap, these are mounted parallel to one another and differ in length. These parallel aprons of varying lengths enable the stream of flue gases to be divided into horizontal or vertical layers, to ensure that the gases flow evenly over the entire cross-section of the tunnel kiln, so that all points in the ware are heated uniformly.

With this arrangement, it is preferably possible to close olf the passages between the individual aprons. By the closing-olf of particular passages between the aprons, the suction of the flue gases can be regulated so that these flow through the lower portion of the zone charged with ceramic ware.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a vertical section, of the charging end, of one embodiment of a kiln in accordance with the invention;

FIG. 2 is a vertical section of the charging end of another embodiment;

FIG. 3 is a vertical section along the line III-III of FIG. 2;

FIG. 4 is a plan of the charging end of a third embodiment;

FIG. 5 is a vertical section along the line V-V of PIG. 4;

FIG. 6 is a plan of the charging end of a fourth embodiment; and

FIG. 7 is a vertical section along the line VII-VII of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The reference numeral 1 has been used to designate a tunnel kiln, only the charging end of which is shown in the drawings. Cars 2 and 2a can be run along the length of this tunnel kiln.

The cars 2 and 2a carry the ceramic ware that is to be fired, such as bricks, for example. Between the charges 3, fire gaps 4 are provided, these normally being situated below vent holes, not shown in the drawings.

The loading flats of the cars interlock and seal off the firing zone form a passage running lengthwise below the tunnel kiln 1 and hence from the atmosphere.

The direction of advance of the cars 2 and 2a is indicated by the arrow X, while the flue gases or the like are drawn otf in the opposite direction indicated by arrow y, towards the charging end of the tunnel ililn 1.

As can be seen from lFIG. l, for example, adjacent the charging end, that is to say at a short distance from the charging door, there is an extraction chamber 6, substantially rectangular in cross-section, which extends right across the width of the tunnel kiln 1 and which opens into one or more extraction pipes 7. An extraction fan 8 serves to draw off the flue gases or the like from the extraction chamber 6, in the direction indicated by an arrow T.

The members 9, 9a, 9b and 9c are aprons, by which the llue gases drawn out are directed in separate layers through passages 10, 10a, 10b and 10c into the extraction chamber 6. These aprons 9 to 9c are movable, so that they can be withdrawn into the extraction chamber 6 as the cars 2 and 2a are being moved in the direction indicated by arrow x, so as not to obstruct the movement of these cars.

The passages 10 to 10c can be closed by means of dampers, 11, 11a, 11b and 11C. In this way, it is possible to draw off the fiue gases at various levels in the tunnel kiln 1.

The aprons 9 to 9c are fitted in such a way that they can be introduced into the lire gap 4 between the charge points 3 or Withdrawn into the extraction chamber 6.

Another embodiment is shown in FIG. 2. Here, instead of four aprons, there is only a single apron 12, containing apertures 13, through which the iiue gases and the like are drawn off, the low pressure in the fire gap 4 and in the extraction chamber 6 causing the gases that pass through the apertures 13 in the apron 12' to be divided up into a number of separate streams. This apron 12 can likewise be introduced into the fire gap 4 or can be raised into the extraction chamber l6 while the cars 2 and 2a are being moved.

FIGS. 4 and 5 illustratey a further embodiment, in which aprons 1'4, 14a, 14b and 14C are fitted vertically and can be introduced into extraction chambers situated laterally of the firing zone 5 of the kiln. The volume of fiue gases drawn off can be regulated by the passages 16, 16a, 16b and 16a` between the various aprons 14, 14a, 14b and 14C, as well as by the use of dampers not shown in FIGS. 4 and 5.

A final embodiment is illustrated in FIGS. 6 and 7.

Here, the apron 17 is made in two parts, both lying in the 30 I claim: 1. In a ceramics kiln means delining a firing zone, into which cars loaded with the ceramic ware to be red can be moved, means defining a fire gap for the removal of combustion gases, the improvement comprising means defining a first gas-extraction chamber situated laterally of one side of the ire gap, means defining a `second gas-extraction chamber situated laterally of the other side of the fire gap, a first set of aprons movable into and out of the first gas extraction chamber, a second set of aprons movable into and out of the second gas extraction chamber, and means for introducing the aprons to and retracting them from the respective gas extraction cham bers the aprons of each set lying parallel to one another and 20 each apron being of a different length relative to other aprons of that set. i

2. A kiln according to claim 1, comprising dampers, and means to move the dampers to close the passages between the aprons.

References Cited UNITED STATES PATENTS 2,975,499 3/1961 Lapp 25-142X 3,108,351 10/1963 Hermans 25-142 FOREIGN PATENTS 1,166,081 3/1964 Germany.

35 I. SPENCER OVERHOLSER, Primary Examiner L. R. FRYE, Assistant Examiner 

